I. Field of the Invention
The invention relates to new methods for treatment of paddy rice. More specifically, it relates to a method of treating paddy rice, wherein a water soluble package containing a viscous or sticky fluid or gel plant protecting agent is placed in the rice paddy such that the agent spreads to form a uniform film, which can coat the rice plants in response to water levels changes in the rice paddy.
II. Discussion of the Related Art
It is well known that paddy rice, as well as most other crops in the world, is commonly infested with many pests, such as insects and weeds.
There are many difficulties in treating paddies in order to control weeds or insects because of the unusual wetland growing conditions used to raise paddy rice in addition to those difficulties found with most crops.
First of all, there are the classical problems of all pesticidal compositions having a pesticidal active ingredient. These products should be applied to the crops in a safe manner and need to be applied in a timely and efficient manner for the composition to have its greatest effect.
The application of an effective amount of these products in a safe manner on crops means that an effective amount of active ingredient is provided to the plant while a minimum amount of the said active ingredient is applied or remains elsewhere, either in the environment, on the application tools or machinery, or onto the persons who are handling these products. A safe manner to apply the active ingredient includes reduced worker exposure to these products, safety for the environment, including spills, and minimized container disposal issues.
The application of these products in an efficient manner means that an effective amount of active ingredient is provided to the plant which needs it, in order to save it from the pests. That is to say, the amount of insecticides afforded to the plant should be large enough to kill the insects attacking or going to attack the plant during a substantial time frame. It also means the amount of herbicides afforded to the plant should be large enough to kill the weeds or to slow down or prohibit the growth of weeds competing with the crop, and this effect should remain during a substantial time frame. Still another requirement is that a uniform or balanced amount of active ingredient should be applied to the plants in order that phytotoxicity and efficacy are well coordinated.
Regarding the paddies, one common method of applying pesticides is to introduce the mixture on the water of the paddy, so that the active ingredient is spread out and dispersed on the surface of the water, and reaches the rice plant so as to have its efficacy directly on the plant at the interface of the water surface and plant.
Rice paddies are fields that can be flooded with water and usually bordered by an elevated dry area or other such edge area. In order to have the active ingredient spread out in a uniform manner, the most practical manner currently used is where the farmer, walks through the flooded area of the paddy, with his feet immersed in water, as he introduces the active ingredient in the water near him. Unfortunately and obviously, a major drawback of this method is to have the farmer, through his feet, permanently in contact with a liquid (the water of the paddy) containing the pesticide.
One solution to the above problems is described in Japanese Patent No. 563-30281 to Nihon Kayaku K.K., published Jul. 29, 1985 and granted on Jun. 17, 1988. The method described in this patent involves use of a powder and dry granules of active ingredient in water soluble packaging. The granules initially sink to the bottom then eventually float on the surface and dissolve in the water. While they avoid the need to walk in the flooded area, granules deliver active at other than the surface, are relatively slow to dissolve and disperse on the surface of the water, are expensive to make and still represent a dusting problem during manufacture, do not coat the surface of the water evenly and may only afford protection at the interface between the film on the water surface and the plant and do not coat the plant under changing water levels in the rice paddy.
There are many methods of treatment of paddy by all kind of agrochemicals, either liquid or solid, but there is a need to find better methods to increase simultaneously the safety for people who are handling the active ingredient and the efficacy of the active ingredient for the plant, i.e. rice plant.